Efficient Solar-driven Steam Generation Enabled by An Ultra-black Paint

TL;DR

This paper introduces an ultra-black paint integrated into a foam-based device to significantly improve solar-driven steam generation efficiency for desalination, achieving high evaporation rates and stability across various conditions.

Contribution

The study presents a novel ultra-black paint and foam device that enhances solar absorption and salt rejection, enabling cost-effective, high-efficiency freshwater production.

Findings

Evaporation rate of 2.48 kg/m²/h under one sun

Daily freshwater yield of 2.8 kg/m² in winter

Stable performance across pH 1 to 14

Abstract

Solar-driven interfacial steam generation for desalination has attracted broad attention. However, a significant challenge still remains for achieving a higher evaporation rate and high water quality, together with a cost-effective and easy-to-manufacture device to provide a feasible solar-driven steam generation system. In this study, a novel ultra-black paint, Black 3.0, serving as a perfect solar absorber is introduced into the hot-pressed melamine foam networks, allowing us to construct an ultra-black (99% absorptance in the solar region) and self-floating evaporation device. The high performing features of effective solar absorptance and salt-rejection capability contribute to a high-to-date evaporation rate of freshwater at 2.48 kg m-2 h-1 under one sun (1 kW m-2). This interfacial solar evaporator has a daily drinkable water yield of 2.8 kg m-2 even in cloudy winter weather and maintains stability in water with a wide range of acidity and alkalinity (pH 1~14). These features will enable the construction of a facilely fabricated, robust, highly-efficient, and cost-effective solar steam generation system for freshwater production.